diff --git a/Backend/EVABackend/EVABackend/Models/EVAContext.cs b/Backend/EVABackend/EVABackend/Models/EVAContext.cs
index b559dbd..d26c715 100644
--- a/Backend/EVABackend/EVABackend/Models/EVAContext.cs
+++ b/Backend/EVABackend/EVABackend/Models/EVAContext.cs
@@ -1,4 +1,5 @@
-using Microsoft.EntityFrameworkCore;
+using System.Reflection.Emit;
+using Microsoft.EntityFrameworkCore;
 using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
@@ -16,6 +17,7 @@ namespace EVABackend.Models
         public DbSet<Instrument> Instrumente { get; set; }
         public DbSet<Raum> Raeume { get; set; }
         public DbSet<Antrag> Antraege { get; set; }
+        public DbSet<UnterrichtTyp> UnterrichtTypen { get; set; }
 
         protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
         {
@@ -27,6 +29,18 @@ namespace EVABackend.Models
             modelBuilder.Entity<KursSchueler>()
                 .HasKey(c => new { c.SchuelerId, c.KursId });
 
+            modelBuilder.Entity<RaumInstrument>()
+                .HasKey(c => new { c.InstrumentId, c.RaumId });
+
+            modelBuilder.Entity<KursInstrument>()
+                .HasKey(c => new { c.InstrumentId, c.KursId });
+
+            modelBuilder.Entity<DozentInstrument>()
+                .HasKey(c => new { c.InstrumentId, c.DozentId });
+
+            modelBuilder.Entity<AntragInstrument>()
+                .HasKey(c => new { c.InstrumentId, c.AntragId });
+
             modelBuilder.Entity<KursSchueler>()
                 .HasOne(c => c.Schueler)
                 .WithMany(c => c.KursSchueler)
@@ -36,6 +50,26 @@ namespace EVABackend.Models
                 .HasOne(c => c.Kurs)
                 .WithMany(c => c.KursSchueler)
                 .HasForeignKey(c => c.KursId);
+
+            modelBuilder.Entity<Kurs>()
+                .HasMany(c => c.Instrumente)
+                .WithOne(c => c.Kurs)
+                .HasForeignKey(c => c.KursId);
+
+            modelBuilder.Entity<Dozent>()
+                .HasMany(c => c.Instrumente)
+                .WithOne(c => c.Dozent)
+                .HasForeignKey(c => c.DozentId);
+
+            modelBuilder.Entity<Raum>()
+                .HasMany(c => c.Instrumente)
+                .WithOne(c => c.Raum)
+                .HasForeignKey(c => c.RaumId);
+
+            modelBuilder.Entity<Antrag>()
+                .HasMany(c => c.Instrumente)
+                .WithOne(c => c.Antrag)
+                .HasForeignKey(c => c.AntragId);
         }
     }
 
@@ -77,7 +111,7 @@ namespace EVABackend.Models
     public class Dozent : Person
     {
         public decimal Stundensatz { get; set; }
-        public virtual ICollection<Instrument> Instrumente { get; set; }
+        public virtual ICollection<DozentInstrument> Instrumente { get; set; }
     }
 
     public class Kurs
@@ -91,7 +125,7 @@ namespace EVABackend.Models
         public int Kuendigungsfrist { get; set; }
         public bool Bestaetigt { get; set; }
         public UnterrichtTyp UnterrichtsTyp { get; set; }
-        public virtual ICollection<Instrument> Instrumente { get; set; }
+        public virtual ICollection<KursInstrument> Instrumente { get; set; }
         public virtual ICollection<Unterricht> Unterrichte { get; set; }
         public virtual ICollection<KursSchueler> KursSchueler { get; set; }
     }
@@ -122,7 +156,7 @@ namespace EVABackend.Models
         [Required]
         public string Name { get; set; }
         public bool Belegt { get; set; }
-        public virtual ICollection<Instrument> Instrumente { get; set; }
+        public virtual ICollection<RaumInstrument> Instrumente { get; set; }
     }
 
     public class Antrag
@@ -132,22 +166,62 @@ namespace EVABackend.Models
         public int Id { get; set; }
         public Schueler Schueler { get; set; }
         public UnterrichtTyp UnterrichtTyp { get; set; }
-        public virtual ICollection<Instrument> Instrumente { get; set; }
+        public int KursId { get; set; }
+        public virtual ICollection<AntragInstrument> Instrumente { get; set; }
     }
 
-    public enum UnterrichtTyp
+    public class UnterrichtTyp
     {
-        Einzel, Gruppe, MusikalischFrueherziehung
+        [Key]
+        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+        public int Id { get; set; }
+        [Required]
+        public string Name { get; set; }
     }
 
     public class Instrument
     {
+        [Key]
+        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
         public int Id { get; set; }
-        public InstrumentTyp InstrumentTyp { get; set; }
+        [Required]
+        public string Name { get; set; }
     }
 
-    public enum InstrumentTyp
+    public class KursInstrument
     {
-        Klavier, Schlagzeug, Geige, Gitarre, Band
+        public int? InstrumentId { get; set; }
+        public Instrument Instrument { get; set; }
+        public int? KursId { get; set; }
+        public Kurs Kurs { get; set; }
+    }
+
+    public class RaumInstrument
+    {
+        public int? InstrumentId { get; set; }
+        public Instrument Instrument { get; set; }
+        public int? RaumId { get; set; }
+        public Raum Raum { get; set; }
     }
+
+    public class DozentInstrument
+    {
+        public int? InstrumentId { get; set; }
+        public Instrument Instrument { get; set; }
+        public int? DozentId { get; set; }
+        public Dozent Dozent { get; set; }
+    }
+
+    public class AntragInstrument
+    {
+        public int? InstrumentId { get; set; }
+        public Instrument Instrument { get; set; }
+        public int? AntragId { get; set; }
+        public Antrag Antrag { get; set; }
+    }
+
+    //public enum InstrumentTyp
+    //{
+    //    Klavier, Schlagzeug, Geige, Gitarre, Band
+    //}
 }